1. Field of the Invention
This invention relates to a tensioning apparatus of the idler roller type for endless power transmission devices, such as, endless belts, sprocket chains, timing belts, and the like.
2. Prior Art Statement .Iaddend.
In numerous applications where endless power transmission devices are employed it is often desirable or necessary to control the tension in such devices during movement thereof around associated sheaves, pulleys, sprockets or the like, to assure optimum operating efficiency.
For example, in the automobile industry where a single endless power transmission belt is used to drive various automobile accessories, a belt tensioning device is required to assure satisfactory performance of the accessories as well as assure satisfactory service life of the belt.
Numerous tensioning devices such as belt tensioning devices have been proposed heretofore and most of these devices employ metal spring devices, hydraulic devices, or pneumatic devices to provide the tensioning action whereby such devices are comparatively complicated and expensive and require considerable maintenance. .Iadd.
It has also been proposed heretofore to employ rubber under loaded or stressed conditions as a resilient spring means in various applications, including tensioning apparatus for endless power transmission devices. However, rubber thus used heretofore has either resulted in comparatively complicated and expensive tensioning apparatus or in such apparatus which requires a skilled mechanic to install same on associated equipment to assure satisfactory performance of such equipment and the tensioning apparatus. .Iaddend.Accordingly, there is a need for a simple and inexpensive tensioning apparatus .Iadd.for an endless power transmission device .Iaddend.capable of providing reliable performance over an extended service life .Iadd.and capable of being installed on associated equipment by a comparatively unskilled person. .Iaddend.